1 Performance Test Methodology
2 ============================
7 Packet and bandwidth throughput are measured in accordance with
8 :rfc:`2544`, using FD.io CSIT Multiple Loss Ratio search (MLRsearch), an
9 optimized binary search algorithm, that measures SUT/DUT throughput at
10 different Packet Loss Ratio (PLR) values.
12 Following MLRsearch values are measured across a range of L2 frame sizes
15 - **Non Drop Rate (NDR)**: packet and bandwidth throughput at PLR=0%.
17 - **Aggregate packet rate**: NDR_LOWER <bi-directional packet rate>
19 - **Aggregate bandwidth rate**: NDR_LOWER <bi-directional bandwidth
22 - **Partial Drop Rate (PDR)**: packet and bandwidth throughput at
25 - **Aggregate packet rate**: PDR_LOWER <bi-directional packet rate>
27 - **Aggregate bandwidth rate**: PDR_LOWER <bi-directional bandwidth
30 NDR and PDR are measured for the following L2 frame sizes (untagged
33 - IPv4 payload: 64B, IMIX_v4_1 (28x64B, 16x570B, 4x1518B), 1518B, 9000B.
34 - IPv6 payload: 78B, 1518B, 9000B.
36 All rates are reported from external Traffic Generator perspective.
38 .. _mlrsearch_algorithm:
43 Multiple Loss Rate search (MLRsearch) is a new search algorithm
44 implemented in FD.io CSIT project. MLRsearch discovers multiple packet
45 throughput rates in a single search, with each rate associated with a
46 distinct Packet Loss Ratio (PLR) criteria.
48 Two throughput measurements used in FD.io CSIT are Non-Drop Rate (NDR,
49 with zero packet loss, PLR=0) and Partial Drop Rate (PDR, with packet
50 loss rate not greater than the configured non-zero PLR). MLRsearch
51 discovers NDR and PDR in a single pass reducing required execution time
52 compared to separate binary searches for NDR and PDR. MLRsearch reduces
53 execution time even further by relying on shorter trial durations
54 of intermediate steps, with only the final measurements
55 conducted at the specified final trial duration.
56 This results in the shorter overall search
57 execution time when compared to a standard NDR/PDR binary search,
58 while guaranteeing the same or similar results.
60 If needed, MLRsearch can be easily adopted to discover more throughput rates
61 with different pre-defined PLRs.
63 .. Note:: All throughput rates are *always* bi-directional
64 aggregates of two equal (symmetric) uni-directional packet rates
65 received and reported by an external traffic generator.
70 The main properties of MLRsearch:
72 - MLRsearch is a duration aware multi-phase multi-rate search algorithm.
74 - Initial phase determines promising starting interval for the search.
75 - Intermediate phases progress towards defined final search criteria.
76 - Final phase executes measurements according to the final search
81 - Uses link rate as a starting transmit rate and discovers the Maximum
82 Receive Rate (MRR) used as an input to the first intermediate phase.
84 - *Intermediate phases*:
86 - Start with initial trial duration (in the first phase) and converge
87 geometrically towards the final trial duration (in the final phase).
88 - Track two values for NDR and two for PDR.
90 - The values are called (NDR or PDR) lower_bound and upper_bound.
91 - Each value comes from a specific trial measurement
92 (most recent for that transmit rate),
93 and as such the value is associated with that measurement's duration and loss.
94 - A bound can be invalid, for example if NDR lower_bound
95 has been measured with nonzero loss.
96 - Invalid bounds are not real boundaries for the searched value,
97 but are needed to track interval widths.
98 - Valid bounds are real boundaries for the searched value.
99 - Each non-initial phase ends with all bounds valid.
101 - Start with a large (lower_bound, upper_bound) interval width and
102 geometrically converge towards the width goal (measurement resolution)
103 of the phase. Each phase halves the previous width goal.
104 - Use internal and external searches:
106 - External search - measures at transmit rates outside the (lower_bound,
107 upper_bound) interval. Activated when a bound is invalid,
108 to search for a new valid bound by doubling the interval width.
109 It is a variant of `exponential search`_.
110 - Internal search - `binary search`_, measures at transmit rates within the
111 (lower_bound, upper_bound) valid interval, halving the interval width.
113 - *Final phase* is executed with the final test trial duration, and the final
114 width goal that determines resolution of the overall search.
115 Intermediate phases together with the final phase are called non-initial phases.
117 The main benefits of MLRsearch vs. binary search include:
119 - In general MLRsearch is likely to execute more search trials overall, but
120 less trials at a set final duration.
121 - In well behaving cases it greatly reduces (>50%) the overall duration
122 compared to a single PDR (or NDR) binary search duration,
123 while finding multiple drop rates.
124 - In all cases MLRsearch yields the same or similar results to binary search.
125 - Note: both binary search and MLRsearch are susceptible to reporting
126 non-repeatable results across multiple runs for very bad behaving
131 - Worst case MLRsearch can take longer than a binary search e.g. in case of
132 drastic changes in behaviour for trials at varying durations.
134 Search Implementation
135 ~~~~~~~~~~~~~~~~~~~~~
137 Following is a brief description of the current MLRsearch
138 implementation in FD.io CSIT.
143 #. *maximum_transmit_rate* - maximum packet transmit rate to be used by
144 external traffic generator, limited by either the actual Ethernet
145 link rate or traffic generator NIC model capabilities. Sample
146 defaults: 2 * 14.88 Mpps for 64B 10GE link rate,
147 2 * 18.75 Mpps for 64B 40GE NIC maximum rate.
148 #. *minimum_transmit_rate* - minimum packet transmit rate to be used for
149 measurements. MLRsearch fails if lower transmit rate needs to be
150 used to meet search criteria. Default: 2 * 10 kpps (could be higher).
151 #. *final_trial_duration* - required trial duration for final rate
152 measurements. Default: 30 sec.
153 #. *initial_trial_duration* - trial duration for initial MLRsearch phase.
155 #. *final_relative_width* - required measurement resolution expressed as
156 (lower_bound, upper_bound) interval width relative to upper_bound.
158 #. *packet_loss_ratio* - maximum acceptable PLR search criteria for
159 PDR measurements. Default: 0.5%.
160 #. *number_of_intermediate_phases* - number of phases between the initial
161 phase and the final phase. Impacts the overall MLRsearch duration.
162 Less phases are required for well behaving cases, more phases
163 may be needed to reduce the overall search duration for worse behaving cases.
164 Default (2). (Value chosen based on limited experimentation to date.
165 More experimentation needed to arrive to clearer guidelines.)
170 1. First trial measures at maximum rate and discovers MRR.
172 a. *in*: trial_duration = initial_trial_duration.
173 b. *in*: offered_transmit_rate = maximum_transmit_rate.
174 c. *do*: single trial.
175 d. *out*: measured loss ratio.
176 e. *out*: mrr = measured receive rate.
178 2. Second trial measures at MRR and discovers MRR2.
180 a. *in*: trial_duration = initial_trial_duration.
181 b. *in*: offered_transmit_rate = MRR.
182 c. *do*: single trial.
183 d. *out*: measured loss ratio.
184 e. *out*: mrr2 = measured receive rate.
186 3. Third trial measures at MRR2.
188 a. *in*: trial_duration = initial_trial_duration.
189 b. *in*: offered_transmit_rate = MRR2.
190 c. *do*: single trial.
191 d. *out*: measured loss ratio.
198 a. *in*: trial_duration for the current phase.
199 Set to initial_trial_duration for the first intermediate phase;
200 to final_trial_duration for the final phase;
201 or to the element of interpolating geometric sequence
202 for other intermediate phases.
203 For example with two intermediate phases, trial_duration
204 of the second intermediate phase is the geometric average
205 of initial_strial_duration and final_trial_duration.
206 b. *in*: relative_width_goal for the current phase.
207 Set to final_relative_width for the final phase;
208 doubled for each preceding phase.
209 For example with two intermediate phases,
210 the first intermediate phase uses quadruple of final_relative_width
211 and the second intermediate phase uses double of final_relative_width.
212 c. *in*: ndr_interval, pdr_interval from the previous main loop iteration
213 or the previous phase.
214 If the previous phase is the initial phase, both intervals have
215 lower_bound = MRR2, uper_bound = MRR.
216 Note that the initial phase is likely to create intervals with invalid bounds.
217 d. *do*: According to the procedure described in point 2,
218 either exit the phase (by jumping to 1.g.),
219 or prepare new transmit rate to measure with.
220 e. *do*: Perform the trial measurement at the new transmit rate
221 and trial_duration, compute its loss ratio.
222 f. *do*: Update the bounds of both intervals, based on the new measurement.
223 The actual update rules are numerous, as NDR external search
224 can affect PDR interval and vice versa, but the result
225 agrees with rules of both internal and external search.
226 For example, any new measurement below an invalid lower_bound
227 becomes the new lower_bound, while the old measurement
228 (previously acting as the invalid lower_bound)
229 becomes a new and valid upper_bound.
230 Go to next iteration (1.c.), taking the updated intervals as new input.
231 g. *out*: current ndr_interval and pdr_interval.
232 In the final phase this is also considered
233 to be the result of the whole search.
234 For other phases, the next phase loop is started
235 with the current results as an input.
237 2. New transmit rate (or exit) calculation (for 1.d.):
239 - If there is an invalid bound then prepare for external search:
241 - *If* the most recent measurement at NDR lower_bound transmit rate
242 had the loss higher than zero, then
243 the new transmit rate is NDR lower_bound
244 decreased by two NDR interval widths.
245 - Else, *if* the most recent measurement at PDR lower_bound
246 transmit rate had the loss higher than PLR, then
247 the new transmit rate is PDR lower_bound
248 decreased by two PDR interval widths.
249 - Else, *if* the most recent measurement at NDR upper_bound
250 transmit rate had no loss, then
251 the new transmit rate is NDR upper_bound
252 increased by two NDR interval widths.
253 - Else, *if* the most recent measurement at PDR upper_bound
254 transmit rate had the loss lower or equal to PLR, then
255 the new transmit rate is PDR upper_bound
256 increased by two PDR interval widths.
257 - If interval width is higher than the current phase goal:
259 - Else, *if* NDR interval does not meet the current phase width goal,
260 prepare for internal search. The new transmit rate is
261 (NDR lower bound + NDR upper bound) / 2.
262 - Else, *if* PDR interval does not meet the current phase width goal,
263 prepare for internal search. The new transmit rate is
264 (PDR lower bound + PDR upper bound) / 2.
265 - Else, *if* some bound has still only been measured at a lower duration,
266 prepare to re-measure at the current duration (and the same transmit rate).
267 The order of priorities is:
273 - *Else*, do not prepare any new rate, to exit the phase.
274 This ensures that at the end of each non-initial phase
275 all intervals are valid, narrow enough, and measured
276 at current phase trial duration.
278 Implementation Deviations
279 ~~~~~~~~~~~~~~~~~~~~~~~~~
281 This document so far has been describing a simplified version of MLRsearch algorithm.
282 The full algorithm as implemented contains additional logic,
283 which makes some of the details (but not general ideas) above incorrect.
284 Here is a short description of the additional logic as a list of principles,
285 explaining their main differences from (or additions to) the simplified description,
286 but without detailing their mutual interaction.
288 1. *Logarithmic transmit rate.*
289 In order to better fit the relative width goal,
290 the interval doubling and halving is done differently.
291 For example, the middle of 2 and 8 is 4, not 5.
292 2. *Optimistic maximum rate.*
293 The increased rate is never higher than the maximum rate.
294 Upper bound at that rate is always considered valid.
295 3. *Pessimistic minimum rate.*
296 The decreased rate is never lower than the minimum rate.
297 If a lower bound at that rate is invalid,
298 a phase stops refining the interval further (until it gets re-measured).
299 4. *Conservative interval updates.*
300 Measurements above current upper bound never update a valid upper bound,
301 even if drop ratio is low.
302 Measurements below current lower bound always update any lower bound
303 if drop ratio is high.
304 5. *Ensure sufficient interval width.*
305 Narrow intervals make external search take more time to find a valid bound.
306 If the new transmit increased or decreased rate would result in width
307 less than the current goal, increase/decrease more.
308 This can happen if the measurement for the other interval
309 makes the current interval too narrow.
310 Similarly, take care the measurements in the initial phase
311 create wide enough interval.
312 6. *Timeout for bad cases.*
313 The worst case for MLRsearch is when each phase converges to intervals
314 way different than the results of the previous phase.
315 Rather than suffer total search time several times larger
316 than pure binary search, the implemented tests fail themselves
317 when the search takes too long (given by argument *timeout*).
319 Maximum Receive Rate MRR
320 ------------------------
322 MRR tests measure the packet forwarding rate under the maximum
323 load offered by traffic generator over a set trial duration,
324 regardless of packet loss. Maximum load for specified Ethernet frame
325 size is set to the bi-directional link rate.
327 Current parameters for MRR tests:
329 - Ethernet frame sizes: 64B (78B for IPv6), IMIX, 1518B, 9000B; all
330 quoted sizes include frame CRC, but exclude per frame transmission
331 overhead of 20B (preamble, inter frame gap).
333 - Maximum load offered: 10GE and 40GE link (sub-)rates depending on NIC
334 tested, with the actual packet rate depending on frame size,
335 transmission overhead and traffic generator NIC forwarding capacity.
337 - For 10GE NICs the maximum packet rate load is 2* 14.88 Mpps for 64B,
338 a 10GE bi-directional link rate.
339 - For 25GE NICs the maximum packet rate load is 2* 18.75 Mpps for 64B,
340 a 25GE bi-directional link sub-rate limited by TG 25GE NIC used,
342 - For 40GE NICs the maximum packet rate load is 2* 18.75 Mpps for 64B,
343 a 40GE bi-directional link sub-rate limited by TG 40GE NIC used,
344 XL710. Packet rate for other tested frame sizes is limited by PCIe
345 Gen3 x8 bandwidth limitation of ~50Gbps.
347 - Trial duration: 10sec.
349 Similarly to NDR/PDR throughput tests, MRR test should be reporting bi-
350 directional link rate (or NIC rate, if lower) if tested VPP
351 configuration can handle the packet rate higher than bi-directional link
352 rate, e.g. large packet tests and/or multi-core tests.
354 MRR tests are used for continuous performance trending and for
355 comparison between releases. Daily trending job tests subset of frame
356 sizes, focusing on 64B (78B for IPv6) for all tests and IMIX for
357 selected tests (vhost, memif).
362 TRex Traffic Generator (TG) is used for measuring latency of VPP DUTs.
363 Reported latency values are measured using following methodology:
365 - Latency tests are performed at 100% of discovered NDR and PDR rates
366 for each throughput test and packet size (except IMIX).
367 - TG sends dedicated latency streams, one per direction, each at the
368 rate of 9 kpps at the prescribed packet size; these are sent in
369 addition to the main load streams.
370 - TG reports min/avg/max latency values per stream direction, hence two
371 sets of latency values are reported per test case; future release of
372 TRex is expected to report latency percentiles.
373 - Reported latency values are aggregate across two SUTs due to three
374 node topology used for all performance tests; for per SUT latency,
375 reported value should be divided by two.
376 - 1usec is the measurement accuracy advertised by TRex TG for the setup
377 used in FD.io labs used by CSIT project.
378 - TRex setup introduces an always-on error of about 2*2usec per latency
379 flow additonal Tx/Rx interface latency induced by TRex SW writing and
380 reading packet timestamps on CPU cores without HW acceleration on NICs
381 closer to the interface line.
386 All performance tests are executed with single processor core and with
387 multiple cores scenarios.
389 Intel Hyper-Threading (HT)
390 ~~~~~~~~~~~~~~~~~~~~~~~~~~
392 Intel Xeon processors used in FD.io CSIT can operate either in HT
393 Disabled mode (single logical core per each physical core) or in HT
394 Enabled mode (two logical cores per each physical core). HT setting is
395 applied in BIOS and requires server SUT reload for it to take effect,
396 making it impractical for continuous changes of HT mode of operation.
398 |csit-release| performance tests are executed with server SUTs' Intel
399 XEON processors configured with Intel Hyper-Threading Disabled for all
400 Xeon Haswell testbeds (3n-hsw) and with Intel Hyper-Threading Enabled
401 for all Xeon Skylake testbeds.
403 More information about physical testbeds is provided in
404 :ref:`tested_physical_topologies`.
409 |csit-release| multi-core tests are executed in the following VPP worker
410 thread and physical core configurations:
412 #. Intel Xeon Haswell testbeds (3n-hsw) with Intel HT disabled
413 (1 logical CPU core per each physical core):
415 #. 1t1c - 1 VPP worker thread on 1 physical core.
416 #. 2t2c - 2 VPP worker threads on 2 physical cores.
417 #. 4t4c - 4 VPP worker threads on 4 physical cores.
419 #. Intel Xeon Skylake testbeds (2n-skx, 3n-skx) with Intel HT enabled
420 (2 logical CPU cores per each physical core):
422 #. 2t1c - 2 VPP worker threads on 1 physical core.
423 #. 4t2c - 4 VPP worker threads on 2 physical cores.
424 #. 8t4c - 8 VPP worker threads on 4 physical cores.
426 VPP worker threads are the data plane threads running on isolated
427 logical cores. With Intel HT enabled VPP workers are placed as sibling
428 threads on each used physical core. VPP control threads (main, stats)
429 are running on a separate non-isolated core together with other Linux
432 In all CSIT tests care is taken to ensure that each VPP worker handles
433 the same amount of received packet load and does the same amount of
434 packet processing work. This is achieved by evenly distributing per
435 interface type (e.g. physical, virtual) receive queues over VPP workers
436 using default VPP round- robin mapping and by loading these queues with
437 the same amount of packet flows.
439 If number of VPP workers is higher than number of physical or virtual
440 interfaces, multiple receive queues are configured on each interface.
441 NIC Receive Side Scaling (RSS) for physical interfaces and multi-queue
442 for virtual interfaces are used for this purpose.
444 Section :ref:`throughput_speedup_multi_core` includes a set of graphs
445 illustrating packet throughout speedup when running VPP worker threads
446 on multiple cores. Note that in quite a few test cases running VPP
447 workers on 2 or 4 physical cores hits the I/O bandwidth or packets-per-
448 second limit of tested NIC.
453 CSIT code manipulates a number of VPP settings in startup.conf for optimized
454 performance. List of common settings applied to all tests and test
455 dependent settings follows.
457 See `VPP startup.conf <https://git.fd.io/vpp/tree/src/vpp/conf/startup.conf?h=stable/1807>`_
458 for a complete set and description of listed settings.
463 List of vpp startup.conf settings applied to all tests:
465 #. heap-size <value> - set separately for ip4, ip6, stats, main
466 depending on scale tested.
467 #. no-tx-checksum-offload - disables UDP / TCP TX checksum offload in DPDK.
468 Typically needed for use faster vector PMDs (together with
470 #. socket-mem <value>,<value> - memory per numa. (Not required anymore
471 due to VPP code changes, should be removed in CSIT-18.10.)
476 List of vpp startup.conf settings applied dynamically per test:
478 #. corelist-workers <list_of_cores> - list of logical cores to run VPP
479 worker data plane threads. Depends on HyperThreading and core per
481 #. num-rx-queues <value> - depends on a number of VPP threads and NIC
483 #. num-rx-desc/num-tx-desc - number of rx/tx descriptors for specific
484 NICs, incl. xl710, x710, xxv710.
485 #. num-mbufs <value> - increases number of buffers allocated, needed
486 only in scenarios with large number of interfaces and worker threads.
487 Value is per CPU socket. Default is 16384.
488 #. no-multi-seg - disables multi-segment buffers in DPDK, improves
489 packet throughput, but disables Jumbo MTU support. Disabled for all
490 tests apart from the ones that require Jumbo 9000B frame support.
491 #. UIO driver - depends on topology file definition.
492 #. QAT VFs - depends on NRThreads, each thread = 1QAT VFs.
497 FD.io CSIT performance lab is testing VPP vhost with KVM VMs using
498 following environment settings:
500 - Tests with varying Qemu virtio queue (a.k.a. vring) sizes: [vr256]
501 default 256 descriptors, [vr1024] 1024 descriptors to optimize for
503 - Tests with varying Linux :abbr:`CFS (Completely Fair Scheduler)`
504 settings: [cfs] default settings, [cfsrr1] CFS RoundRobin(1) policy
505 applied to all data plane threads handling test packet path including
506 all VPP worker threads and all Qemu testpmd poll-mode threads.
507 - Resulting test cases are all combinations with [vr256,vr1024] and
508 [cfs,cfsrr1] settings.
509 - Adjusted Linux kernel :abbr:`CFS (Completely Fair Scheduler)`
510 scheduler policy for data plane threads used in CSIT is documented in
511 `CSIT Performance Environment Tuning wiki <https://wiki.fd.io/view/CSIT/csit-perf-env-tuning-ubuntu1604>`_.
512 - The purpose is to verify performance impact (MRR and NDR/PDR
513 throughput) and same test measurements repeatability, by making VPP
514 and VM data plane threads less susceptible to other Linux OS system
515 tasks hijacking CPU cores running those data plane threads.
517 LXC/DRC Container Memif
518 -----------------------
520 |csit-release| includes tests taking advantage of VPP memif virtual
521 interface (shared memory interface) to interconnect VPP running in
522 Containers. VPP vswitch instance runs in bare-metal user-mode handling
523 NIC interfaces and connecting over memif (Slave side) to VPPs running in
524 :abbr:`Linux Container (LXC)` or in Docker Container (DRC) configured
525 with memif (Master side). LXCs and DRCs run in a priviliged mode with
526 VPP data plane worker threads pinned to dedicated physical CPU cores per
527 usual CSIT practice. All VPP instances run the same version of software.
528 This test topology is equivalent to existing tests with vhost-user and
529 VMs as described earlier in :ref:`tested_logical_topologies`.
531 In addition to above vswitch tests, a single memif interface test is
532 executed. It runs in a simple topology of two VPP container instances
533 connected over memif interface in order to verify standalone memif
534 interface performance.
536 More information about CSIT LXC and DRC setup and control is available
537 in :ref:`container_orchestration_in_csit`.
542 |csit-release| includes tests of VPP topologies running in K8s
543 orchestrated Pods/Containers and connected over memif virtual
544 interfaces. In order to provide simple topology coding flexibility and
545 extensibility container orchestration is done with `Kubernetes
546 <https://github.com/kubernetes>`_ using `Docker
547 <https://github.com/docker>`_ images for all container applications
548 including VPP. `Ligato <https://github.com/ligato>`_ is used for the
549 Pod/Container networking orchestration that is integrated with K8s,
550 including memif support.
552 In these tests VPP vswitch runs in a K8s Pod with Docker Container (DRC)
553 handling NIC interfaces and connecting over memif to more instances of
554 VPP running in Pods/DRCs. All DRCs run in a priviliged mode with VPP
555 data plane worker threads pinned to dedicated physical CPU cores per
556 usual CSIT practice. All VPP instances run the same version of software.
557 This test topology is equivalent to existing tests with vhost-user and
558 VMs as described earlier in :ref:`tested_physical_topologies`.
560 Further documentation is available in
561 :ref:`container_orchestration_in_csit`.
566 VPP IPSec performance tests are using DPDK cryptodev device driver in
567 combination with HW cryptodev devices - Intel QAT 8950 50G - present in
568 LF FD.io physical testbeds. DPDK cryptodev can be used for all IPSec
569 data plane functions supported by VPP.
571 Currently |csit-release| implements following IPSec test cases:
573 - AES-GCM, CBC-SHA1 ciphers, in combination with IPv4 routed-forwarding
574 with Intel xl710 NIC.
575 - CBC-SHA1 ciphers, in combination with LISP-GPE overlay tunneling for
576 IPv4-over-IPv4 with Intel xl710 NIC.
578 TRex Traffic Generator
579 ----------------------
584 `TRex traffic generator <https://wiki.fd.io/view/TRex>`_ is used for all
585 CSIT performance tests. TRex stateless mode is used to measure NDR and
586 PDR throughputs using binary search (NDR and PDR discovery tests) and
587 for quick checks of DUT performance against the reference NDRs (NDR
588 check tests) for specific configuration.
590 TRex is installed and run on the TG compute node. The typical procedure
593 - If the TRex is not already installed on TG, it is installed in the
594 suite setup phase - see `TRex intallation`_.
595 - TRex configuration is set in its configuration file
600 - TRex is started in the background mode
603 $ sh -c 'cd <t-rex-install-dir>/scripts/ && sudo nohup ./t-rex-64 -i -c 7 --iom 0 > /tmp/trex.log 2>&1 &' > /dev/null
605 - There are traffic streams dynamically prepared for each test, based on traffic
606 profiles. The traffic is sent and the statistics obtained using
607 :command:`trex_stl_lib.api.STLClient`.
609 Measuring Packet Loss
610 ~~~~~~~~~~~~~~~~~~~~~
612 Following sequence is followed to measure packet loss:
614 - Create an instance of STLClient.
615 - Connect to the client.
618 - Send the traffic for defined time.
619 - Get the statistics.
621 If there is a warm-up phase required, the traffic is sent also before
622 test and the statistics are ignored.
627 If measurement of latency is requested, two more packet streams are
628 created (one for each direction) with TRex flow_stats parameter set to
629 STLFlowLatencyStats. In that case, returned statistics will also include
630 min/avg/max latency values.
632 HTTP/TCP with WRK tool
633 ----------------------
635 `WRK HTTP benchmarking tool <https://github.com/wg/wrk>`_ is used for
636 experimental TCP/IP and HTTP tests of VPP TCP/IP stack and built-in
637 static HTTP server. WRK has been chosen as it is capable of generating
638 significant TCP/IP and HTTP loads by scaling number of threads across
639 multi-core processors.
641 This in turn enables quite high scale benchmarking of the main TCP/IP
642 and HTTP service including HTTP TCP/IP Connections-Per-Second (CPS),
643 HTTP Requests-Per-Second and HTTP Bandwidth Throughput.
645 The initial tests are designed as follows:
647 - HTTP and TCP/IP Connections-Per-Second (CPS)
649 - WRK configured to use 8 threads across 8 cores, 1 thread per core.
650 - Maximum of 50 concurrent connections across all WRK threads.
651 - Timeout for server responses set to 5 seconds.
652 - Test duration is 30 seconds.
653 - Expected HTTP test sequence:
655 - Single HTTP GET Request sent per open connection.
656 - Connection close after valid HTTP reply.
657 - Resulting flow sequence - 8 packets: >Syn, <Syn-Ack, >Ack, >Req,
658 <Rep, >Fin, <Fin, >Ack.
660 - HTTP Requests-Per-Second
662 - WRK configured to use 8 threads across 8 cores, 1 thread per core.
663 - Maximum of 50 concurrent connections across all WRK threads.
664 - Timeout for server responses set to 5 seconds.
665 - Test duration is 30 seconds.
666 - Expected HTTP test sequence:
668 - Multiple HTTP GET Requests sent in sequence per open connection.
669 - Connection close after set test duration time.
670 - Resulting flow sequence: >Syn, <Syn-Ack, >Ack, >Req[1], <Rep[1],
671 .., >Req[n], <Rep[n], >Fin, <Fin, >Ack.
673 .. _binary search: https://en.wikipedia.org/wiki/Binary_search
674 .. _exponential search: https://en.wikipedia.org/wiki/Exponential_search
675 .. _estimation of standard deviation: https://en.wikipedia.org/wiki/Unbiased_estimation_of_standard_deviation
676 .. _simplified error propagation formula: https://en.wikipedia.org/wiki/Propagation_of_uncertainty#Simplification